Apparatus for the transmission and receipt of electrical energy.



R. ALFESSENDEN. APPARATUS FOR THE TRANSMISSION AND RECEIPT OF ELECTRICAL ENERGY.

' APPLICATION FILED NOV-22 5190]. RENEWED FEB- 19, I915- l llflfi o Patented J 11110 1.-- 1915.

' I To all whom it may concern:

ing at Brant Rock, inithe county of REGINALD A.' EEss NnEn, ,0]? Bean: 3901:, vras sacnusnr'rs, assrenoa, s r nEsnn 'ASSIGNMENTS, To SAMUEL M. ,K KYT Q TTSBU NNS A AN HALSEY M. BARRETT, or BLQoMEIELD, NEW JERSEY, nEc wEas.

APPARATUS FOR THE TRANSMISSION AND REGEIPT-OF ELECTRICAL -Specification of Letters Patent.

lPatented June-1,1191%.

Original application filed August 426, 1904,: Serial No. 222,301. Divided unas-e n n e anan ber E222,1907, s ri l No. 103 286. Renewed February 19, 1915. .-Ser1a11$lo.: 9,417.

- Be it known-that I, REGINALD A. E ssEn- DEN, a citizen of the Unitedfitates, resid- Plymouth, State of Massachusetts, .have ,invented certain new and usefulvnpparatus for the Transmission and Receipt of Electrical Energy, of which-the-followingis a specification.

The invention herein described relates generally to the transmission and receipt of electrical energy andmore particularly to telegraphy by means of oscillating currents and still more specifically to wirelesstelegraphy by means of electro-magnetic waves.

This application is a division of-my 00-, pending application No. 222,301 filed August 26th, 1904, and the process here set forth is claimed in my other divisional appliczation No. 403,285, of November 22d, 190

In the accompanying drawing Figure 1 is a diagram illustrating receiving appara- 1 tus;-and Fig. 2 shows a modified form for mounting the coils therein. Figs. 3 and 4: illustrate modified arrangements as .will hereinafter be described. 1

In the practice ,of thisinvent-ion I employ for producing an indication,..the interaction between currents 'or voltages produced by the received oscillations, (preferably the former) and currents or voltages produced by a local. source which is practically continuous in operation and which generatesoscillations of afrequency different from the oscillations received,.such {difference of, frequency being preferably slight and of predetermined degree.

Thus in Fig. 1, 1 is an, aerial grounded at 2, 3 the primary of a transformer whose secondary 4 forms part of a circuit compfrising a condenser 5, a coil 6, and with or with outthe additional inductance 66. 14: is a coil placed in inductive, relation to the coil 6. The coil 6 may, if.:desired, have a magnetic core 10, as shown in Fig. 2, preferably consisting of extremely fine iron wire or sheet. The coil 14 is preferably fastened to a diaphragm or spring? .and maybe used directly as a telephone, or; otherwise as shown in Fig. 2, it may move the contact or microphone 13 attached to it and con- :bynieans of a transformer ,8, 9, with: the

tuned to the frequency of the oscillationswhich it is desired to receive. ;The currents generated inthe coil 6- by the received oscillations interact with the magnetic field produced in 14 by the source 17. Obviously, as an alternative to the arrangement of Fig. l, the coil 6 maybe attached to the diaphragm 7, and l l may be fixed. -The describ d interaction between the two fields produced -by the two coils ca ms the diaphragmlto ,move and produce an indication, preferably by the beats produced. A much stronger indication is produced by this interaction between the currents generated by the received electro-magnetic Waves and the locally generated magnetic field than-would be produced by the currents due to the received .wavesalone, because the locally generatedmagnetic field may be made to have any strength desired.

It is characteristic of this invention that the locally generated alternating magnetic field is excitedcontinuously and not intermittently as. by a spark discharge. The duration of a single oscillation produced by a spark is in the neighborhood of one four: mllllODfth of a second. If we consider a train of twenty oscillations or twenty complete waves, such as is commonly used in this art, this. train of waves will,last for approximately oneone-hundred-thohsandths of a second. ,jEyen if the train of waves should be rolonged to one hundred complete .perio s, the total duration of the train of waves would only be one twenty-thdin producing elecsandths ,of a second. The apparatus com- .monl .usedcin the 'artfor .trica d scharges gives from ve to one huntion of a train of waves by a local source generating merely successive separate trains of waves rather than continuous osc1lla tions, 15 only as one to two hundred, and any practical coincidence couldnot be expected more than once in several seconds. It is" also characteristic of my method and of this apparatus that the frequency of the locally generatedmagnctic field should not be exactly the same as that of the oscillations which it desired to receive, for in this case the chancesare even that the phasedifference should be such that no indication would be produped, since no slow beats are produced. It is furthermore preferred that 4 the difference in frequency should be small,

because if the difference in. frequency be large, the beats will. occiir'at such rapid lIltGl'YfilS as to produce an inaudible indication, where a telephone diaphragm is used as in indicator, or else a weak indication,

- through'the inability of the diaphragm or spring 7 to respond quickly.

It will be evident that the number of beats produced per second will depend. upon the diiference between the transmitted frequency and the local frequency, and as this may be varied, this affords a means of distinguishing between different stations, and,

where the receiving mechanism is made selective to the beat frequency, means of cutting out all stations except thcsewith which it is desired to communicate. I

Where the signals are produced by the interaction of voltages insteadof currents a corresponding appropriate type of receiver is used, as for example an electrostatic telephone receiver. This method may be used forsimultaneously sending and receiving, as shown in Fig. 2, where a source of oscillating currents 25 is operatively connected to the wireless conductor 1, 2' and so arrangedas to genera tc oscillations in the aerial 1. This source is also operatively connected, .as by the transformer 68, 69 (with or without the use of the capacity 27,) with the coil 14, in such a way that when the key 78 is dcprcsscd so as to cause oscillations to be generated in the wireless conductor, (by thusclosing the circuitcontaining the field coil 76 and local battery 77 as is well known,) oscillations of the same frequency and of the same duration are caused to oc- 25 upon the receiver is neutralized and may .be rendered entirely inappreciable, espe-- cially Where the receiver istuned to respond to a given mechanical frequency; thus allowing sending without disturbing the receiving apparatus. The condenser 27 also may be used for controlling the phase of the I oscillations generated in the circuit 68, 27 25.

Fig. 3 shows an alternative arrangement wherein the coils 6 and 14: are both mounted upon a single magnetic core '10, the dia-' phragm or spring 7 having a piece of finely laminated magnetic material .7 fastened to it. By the interaction of the two coils the diaphragm is affected similarly as when making one ofthe coils 6 and 14 fixed and the other coil fastened to the diaphragm or spring 7. p

Fig. 4 shows another modification, in which 1 is the aerial grounded at 2, 3 is the primary of a transformer, 4 is the secordary of a transformer, and 16 is a stretched wire in the circuit of the' secondary of the transformer, whichsecondary is preferably tuned by the use of an inductance 70 and capacity 71. I The wire 16 is prefefably tuned to the desired mechanical frequency,

2'. 0., it swings to the frequency of the beats between the received and the locally produced oscillations. 10 is a magnetic core of a coil 14, made of finely laminated wire or I sheet, embracing the wire 16; and the coil 14 is o eratively'connected with a local source 1 which may be a high frequency dynamo, designed to produce the oscillations. In operation the currents generated by the received electro-magnetic waves produce a field which interacts with the magnetic field generated in the magnet coil 14:

and core by the local source, and this causes the wire to vibrate with the frequency of the beats, thereby producing an indication.

In the following claims the term alternating currents is intended *to include oscillating currents, or. all currents varying periodically in intensity, whether or not the sign of the oscillations be changed.

While I have described herein the operation by the received waves and locally produced waves of differing frequency in order to form beats, I have not claimed a specific mode of'operation herein or the apparatus therefor, but the same is claimed in my copending but subsequently filed applications Nos. 271,539 and 275,165 being now Patents 1,050,111 and 1,050,728, respectively, the

agendas claims herein being obviously not limited to beats or to a separate regulator at the receiving end or constant sending.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent, is the following: I

1. An indicator for received alternating currents comprising a local oscillations producer and devices forming a field of force continuously excited thereby, a field excited by the received oscillations, and means operated by the cotiperation of said two fields for producing signals, the whole being adapted to annul the influence of the locally generated field on the indicator when the field for excitation by the received oscillations is not excited.

2. An indicator for alternating currents comprising a coil excited by received curously acting local source of oscillations and a receiver field excited thereby, a second local producing source, and means for an nulling its effect on'the receiver field, substantially as-described.

4:. In wireless telegraphy, the combination with a receiving device comprising a local source of continuous oscillations, of a send ing source of oscillations, and means for annulling the effect of said sending. source on the receiver whereby to send and receive siinultaneously.

5. In wireless signaling the combination at a receiving station of devices forming a field of force excited by oscillations received, devices forming a supplementary field and local means for exciting it, an indicating instrument operated by interactionof said two fields, a sendlng source, and

means in the locally excited field to counteract the efiect of sending oscillations on the field excited by received oscillations whereby to prevent disturbance of the receiving instrument: Y

6. The combination with a generator and a connected antenna of devices forming a field inductively connected with the antenna andexcited by oscillations received thereby,

devices forming a supplementary field and local means for continuously exciting it, indicating means operated by said two fields, and-connections between the generator and the locally excited field to counteract by etfects in the latter the effects in the receiving field of oscillations sent, substantially as described.

In testimonyv whereof I have hereunder signed my name in the presence of the sub scribed witnesses.

REGINALD A. FESSENDEN.

Witnesses:

JEssIE E. BENT, ADnLnINn W. HAER. 

